The invention relates to bumpers for motor vehicles and the like, and in particular to a bumper system that includes a cross-member and crush boxes in accordance with the features of patent claim 1.
Bumper systems comprise individual components that have been designed to work together to absorb energy in a defined manner in the event of an accident. In addition, the bumpers must be designed for various types of collisions. In prior or classic car body constructions, the bumpers are produced from structural components made of welded steel and are therefore relatively heavy.
If alternative materials, such as aluminum, are used due to their lower specific weight, it is very important that the safety standards or classification for the motor vehicle be maintained, even if it has light-weight bumpers.
One possibility in reducing weight in bumper systems is a hybrid construction. Steel components are replaced with structural components made of aluminum. Unfortunately, the combination of aluminum and steel cannot be welded because the melting points for the individual materials are so different.
In the prior art there are for instance hybrid-construction bumpers comprising aluminum and steel. Steel cross members are bolted to aluminum crush boxes, or aluminum cross members are bolted to steel crush boxes. This type of mechanical fastener joining is complex, expensive, and the joining elements are relatively heavy. The bolted joining technique also has a negative impact on the overall component weight.